Abstract Despite increasing recognition that BPA has harmful effects on the reproductive, nervous and immune systems. While higher urine BPA concentrations are associated with cardiovascular disease in humans, the effect(s) of BPA at environmentally relevant concentrations on the heart is unknown. The Specific Aim of the proposed studies is to elucidate the in vivo sex-specific impacts that BPA has on cardiac physiology, to understand the underlying modes and mechanisms of action, and ultimately improve heart health through understanding the impact of pathological actions of exposure to BPA as a protypical environmental EDCs. The central hypothesis of the proposed studies is during development BPA negatively impacts cardiac function which may manifest later in life. We hypothesis that the harmful effects of BPA exposure will impact Ca2+ handling, and that developmental exposures may alter the normal sex-specific actions of estrogen in the heart, and negatively impact heart health by increasing arrhythmias, altering hemodynamic functions of the heart, and increasing cardiac dysfunction in response to physiologic conditions of stress (e.g. catecholamine and pressure overload induced hypertrophy/heart failure). As its primary endpoints, the proposed studies focus on understanding the cardiac-specific actions of BPA. However, the proposal is far more crosscutting, and not limited to a single organ or system-based endpoint. Along with the cardiac specific end-points, we will characterize a number of physiological and reproductive endpoints "classically" used to assess estrogenic EDC activity. This will allow direct comparison of results obtained in the "estrogen-sensitive" C57BL/6J strain with studies performed in the "insensitive" CD1 (Swiss) mouse. Detailed physiological phenotype data will be collected for all animals and at termination of the study complete necropsy will be performed with tissues from all organs harvested, collected and prepared for histological studies with paired samples preserved for future molecular, epigenetic, and "omics" analysis. As a result of the proposed studies we will create a defining framework and knowledge base necessary to standardize future studies that employee C57BL/6J derived genetic mouse models, and allow systematic investigation of the mechanisms of action of BPA using knockout and transgenic models.